JP2013040798A - Fluorescence sensor and fluorescence sensor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescence sensor 30 capable of performing accurate measurement.SOLUTION: A fluorescence sensor 30 according to an embodiment comprises: a substrate 11; a PD element 12 that converts fluorescent light into an electrical signal; a sensor frame 17 constituting the side surfaces of an indicator space 16 in which a dry indicator 19 formed from a hydrogel generating fluorescent light by means of analyte and excitation light is housed; a filter 13 provided in such a manner that the filter 13 covers the PD element 12; an LED element 14 generating fluorescent light; a transparent middle layer 15 constituting the bottom surface of the indicator space 16; a light-shielding layer 18 constituting the upper surface of the indicator space 16, and a PD element 20 functioning as a swelling detection sensor for detecting the swelling of the indicator 19.

Description

  The present invention relates to a fluorescence sensor for measuring the concentration of an analyte in an aqueous solution and a fluorescence sensor system having the fluorescence sensor, and in particular, a fluorescence sensor comprising an indicator made of an analyte and a hydrogel that generates fluorescence by excitation light, and The present invention relates to a fluorescence sensor system having the fluorescence sensor.

  A fluorescent sensor for measuring the concentration of an analyte in a liquid, that is, a substance to be measured has been developed. The fluorescence sensor has an indicator that generates fluorescence F having a light amount corresponding to the analyte concentration when receiving excitation light, and a photoelectric conversion element that detects fluorescence from the indicator.

  For example, the fluorescent sensor 130 disclosed in US Pat. No. 5,039,490 can be manufactured using the MEMS technology and can be miniaturized. As shown in FIGS. 1 and 2, the fluorescence sensor 130 includes a transparent substrate 111 that can transmit the excitation light E, a photoelectric conversion element 112 that converts the fluorescence F into an electric signal, and a condensing light that collects the excitation light E. It is composed of a transparent intermediate layer 115 having a functional part 115A, an indicator 119 that emits fluorescence F having a light amount corresponding to the analyte concentration by the action of the analyte 2 and the excitation light E, and a light shielding layer 118.

  In the fluorescence sensor 130, only the excitation light E2 that has passed through the gap 112B between the photoelectric conversion element 112 and the photoelectric conversion element substrate 112A of the excitation light E incident from the lower surface of the transparent substrate 111 is incident on the indicator 119.

  On the other hand, US Pat. No. 7,181,096 discloses a fluorescent sensor using a hydrogel as an indicator. Since the hydrogel is easy for the analyte to enter, the fluorescence sensor using the hydrogel as the indicator has good sensitivity.

  However, the characteristics of a fluorescent sensor using hydrogel as an indicator may change with the passage of time from manufacture to use. For this reason, a known fluorescent sensor using hydrogel as an indicator may not be able to easily measure the analyte concentration accurately.

US Pat. No. 5,039,490 U.S. Pat. No. 7,181,096

  An object of an embodiment of the present invention is to provide a fluorescent sensor capable of accurate measurement and a fluorescent sensor system having the fluorescent sensor.

  In the fluorescence sensor of one embodiment of the present invention, a substrate, a first photoelectric conversion element that converts fluorescence into an electric signal, and an indicator that includes a hydrogel that generates fluorescence by an analyte and excitation light are contained in a dry state. A sensor frame forming a side surface of the indicator space, a filter disposed so as to cover the photoelectric conversion element and transmitting the fluorescence and blocking the excitation light, and the excitation light disposed in the sensor frame. A transparent intermediate layer disposed on the light emitting element constituting the lower surface of the indicator space disposed in the sensor frame, an upper surface of the indicator space, and an outer surface A light-blocking layer that blocks light and the excitation light and allows passage of bodily fluids including the analyte, and detects swelling of the indicator due to the ingress of the bodily fluids into the indicator space. Swelling detection sensor comprises a.

  A fluorescent sensor system according to another aspect of the present invention includes the fluorescent sensor described above, and a main body unit that is connected to the fluorescent sensor and has a control unit that controls the operation of the fluorescent sensor. However, the measurement of the analyte concentration is started based on the detection signal output from the swelling detection sensor.

  According to the embodiment of the present invention, it is possible to provide a fluorescent sensor capable of accurate measurement and a fluorescent sensor system having the fluorescent sensor.

It is explanatory drawing which showed the cross-section of the conventional fluorescence sensor. It is the exploded view which showed the structure of the conventional fluorescence sensor. It is a mimetic diagram of a needle type sensor system of a 1st embodiment. It is a cross-sectional schematic diagram for demonstrating the puncture of the needle type sensor of 1st Embodiment. It is the exploded view which showed the structure of the fluorescence sensor of 1st Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 1st Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 1st Embodiment. It is a graph for demonstrating operation | movement of the swelling detection sensor of the fluorescence sensor of 1st Embodiment. It is a flowchart for demonstrating operation | movement of the fluorescence sensor system of 1st Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 2nd Embodiment. It is the figure which observed the board | substrate and sensor frame of the fluorescence sensor of 2nd Embodiment from the top. It is the exploded view which showed the structure of the fluorescence sensor of 3rd Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 3rd Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 4th Embodiment.

<First Embodiment>
<Configuration of fluorescence sensor system>
Hereinafter, a fluorescent sensor (hereinafter referred to as “sensor”) 30 and a fluorescent sensor system (hereinafter referred to as “sensor system”) 1 according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 3, the sensor 30 is used as the sensor system 1 in combination with the main body 40 and the receiver 45. That is, the sensor system 1 includes a sensor 30, a main body 40, and a receiver 45 that receives and stores a signal from the main body 40. The connector part 35 of the sensor 30 is detachably fitted to the fitting part 41 of the main body part 40. The sensor 30 is electrically connected to the main body portion 40 by mechanically fitting the connector portion 35 with the fitting portion 41 of the main body portion 40. Transmission / reception of signals between the main body 40 and the receiver 45 is performed wirelessly or by wire. In addition, when the main body 40 has a receiver function, the receiver 45 is unnecessary.

  The sensor 30 includes a distal end portion 32, a needle main body portion 33 extending from the distal end portion 32, and a connector portion 35 extending from the needle main body portion 33. The distal end portion 32, the needle main body portion 33, and the connector portion 35 are produced, for example, by processing a silicon substrate. In particular, the boundary between the distal end portion 32 and the needle main body portion 33 may not be clear.

  The main body 40 includes a control unit 42 that controls the operation of the sensor 30, a wireless antenna that wirelessly transmits and receives signals to and from the receiver 45, a power source such as a battery, and various circuits. Examples of the various circuits include an amplifier circuit that amplifies signals, a circuit reference clock generation circuit, a logic circuit, a data processing circuit, an AD conversion processing circuit, a mode control circuit, a memory circuit, and a communication high-frequency generator circuit. be able to. In addition, when transmitting and receiving a signal with the receiver 45 by wire, the main-body part 40 has a signal line instead of a wireless antenna. Information such as the analyte concentration in the body fluid measured by the sensor unit 10 is stored in the memory of the receiver 45.

  The sensor 30 is a disposable part that is disposed of after use to prevent infection, but the main body 40 and the receiver 45 are reusable parts that are repeatedly reused.

  As shown in FIG. 4A, the sensor 30 is inserted into the dermis layer of the subject 90, for example, by the subject himself puncturing from the body surface while being accommodated in the hollow portion of the sheath tube 50. . Then, as shown in FIG. 4B, before starting the measurement of the analyte concentration, only the sheath tube 50 is removed leaving the tip 32 in the body. That is, the distal end portion 32 is left in the body. The sheath tube 50 is a hollow so-called outer needle having a sharp tip, and is an auxiliary tool for puncturing the subject with the sensor 30. That is, the sheath tube 50 has at least the tip portion 32 of the sensor 30 in the hollow portion. The subject is punctured in a state in which it is accommodated. Then, the sensor 30 is left in the body, the sheath tube 50 is removed, and the main body 40 is connected to the sensor 30.

<Configuration of fluorescence sensor>
Next, as shown in FIGS. 5 and 6, the sensor 30 includes a substrate 11, a filter 13, an LED element 14 that is a light emitting element, a transparent intermediate layer 15, an indicator 19, and a light shielding layer 18. It is a structure laminated in order. In the indicator space 16 in which the indicator 19 is accommodated, the lower surface is the transparent intermediate layer 15, the upper surface is the light shielding layer 18, and the side surface is the sensor frame 17. The shape of the indicator space 16 is a rectangular parallelepiped (square column shape), but may be a columnar shape, a polygonal column shape, or the like.

  The substrate 11 includes a photodiode element (hereinafter referred to as “PD element”) 12 that is a first photoelectric conversion element, and a PD element 20 that is a second photoelectric conversion element that is a swelling detection sensor. Since the filter 13 disposed so as to cover the PD element 12 transmits the fluorescence F and blocks the excitation light E, the PD element 12 outputs an electrical signal corresponding to the intensity of the incident fluorescence F. On the other hand, the filter 13 is not disposed on the PD element 20. For this reason, the PD element 20 outputs an electrical signal corresponding to the intensity of the excitation light E that is stronger than the fluorescence F. A filter that transmits the excitation light E and blocks the fluorescence F may be provided so as to cover the PD element 20.

  The LED element 14 disposed on the filter 13 generates excitation light E. The indicator 19 is made of a hydrogel having a fluorescent dye that generates fluorescence F by the excitation light E and the analyte 2 that has entered after passing through the light shielding layer 18. In the sensor 30, glucose is the analyte 2.

  In the sensor 30, the excitation light E generated by the LED element 14 is efficiently applied to the indicator 19. Further, in the sensor 30, a part of the fluorescence F generated by the indicator 19 passes through the PD element 12 and the filter 13 and enters the PD element 12. For this reason, the sensor 30 has higher sensitivity than the conventional fluorescent sensor 130 described above.

  And the inventor discovered that the time-dependent change of the characteristic of the fluorescence sensor using hydrogel before use did not generate | occur | produce in a dry state hydrogel (indicator). That is, if the indicator is in a dry state before use and is in a water-containing state at the start of use, the characteristics of the fluorescent sensor at the time of use are stable even after long-term storage.

  In the sensor 30, the indicator 19 is in a dry state before use. That is, before use, the indicator space 16 is occupied by a dry indicator 19 and a gas such as air. Then, as shown in FIG. 5, when inserted into the body at the start of use, the indicator 19 swells by absorbing body fluid such as blood, that is, water through the light shielding layer 18.

  In addition, before inserting in a body, the sensor 30 may be immersed in the physiological saline etc. and the indicator 19 may be swollen beforehand. However, it is preferable that the indicator 19 is swollen with a body fluid containing an analyte because a stable measurement state can be obtained earlier.

  The sensor 30 can measure the analyte concentration continuously for a predetermined period, for example, one week after being inserted into the body. However, the collected body fluid or the body fluid that circulates through the body through a flow path outside the body may be brought into contact with the sensor 30 outside the body without inserting the sensor 30 into the body.

Next, components of the sensor 30 will be described in detail.
As already described, the substrate 11 includes the PD element 12 and the PD element 20. The PD element 12 is an analyte measurement sensor, and the PD element 20 is a swelling detection sensor.

In order to form the PD element 12 and the PD element 20, for example, the conditions for implanting boron (B) into the silicon wafer as the substrate 11 are: acceleration voltage: 10 to 100 keV, implantation amount: 1 × 10 ¹⁵ cm. ^-2 or so. The PD element 12 and the PD element 20 can be simultaneously formed by using a mask pattern.

  That is, as the substrate, a semiconductor substrate such as silicon is suitable when the PD element 12 or the like is formed on the main surface by a semiconductor manufacturing technique, but a glass substrate or the like depending on a manufacturing method or an arrangement position of the PD element 12 or the like. But you can. Further, a photoconductor, a phototransistor, or the like may be used as the photoelectric conversion element.

  The filter 13 is disposed so as to cover the PD element 12 that is a light receiving unit. The filter 13 blocks, for example, the excitation light E having a wavelength of 375 nm generated by the LED element 14 disposed on the filter 13, but transmits the fluorescence F having a wavelength of 460 nm generated by the indicator 19.

  The filter 13 may be a multiple interference filter, but is preferably a light absorption filter, for example, a single layer made of silicon, silicon carbide, silicon oxide, silicon nitride, or an organic material, or the single layer It is a multilayer layer formed by laminating.

  The filter 13 may be disposed on the PD element 12 via a transparent protective layer made of, for example, silicon oxide or silicon nitride. However, the filter 13 is preferably disposed as close as possible to the PD element 12 in order to prevent light from entering from the side surface of the protective layer. Further, if there is a space between the PD element 12 and the filter 13, an optical loss occurs and the transmittance decreases. For this reason, it is particularly preferable that the filter 13 is disposed in close contact with the PD element 12.

  As the light emitting element, an element that transmits the fluorescence F is selected from light emitting elements that emit desired excitation light E, such as an LED element, an organic EL element, an inorganic EL element, or a laser diode element.

  As the light emitting element, an LED element is preferable from the viewpoints of fluorescence transmittance, light generation efficiency, wide wavelength selectivity of excitation light E, and generation of a little light other than the wavelength having excitation action. . Further, among LED elements, an ultraviolet LED element made of a gallium nitride compound semiconductor formed on a sapphire substrate having high fluorescence F transmittance is particularly preferable.

  For the transparent intermediate layer 15, quartz, glass, silicone resin, or transparent amorphous fluororesin is preferably used, and among them, silicone resin or transparent amorphous fluororesin is particularly preferable.

  The transparent intermediate layer 15 may not be provided, and the upper surface of the LED element 14 may constitute the lower surface of the indicator space 16. That is, a sapphire substrate having a light emitting portion formed on the lower surface may have a function as the transparent intermediate layer 15.

  The indicator 19 is made of a hydrogel having a fluorescent dye that generates fluorescence F having a longer wavelength than the excitation light E by the analyte 2 and the excitation light E. In other words, the indicator 19 is composed of a hydrogel that contains the fluorescent dye that generates the fluorescence F with a light amount corresponding to the analyte concentration in the sample and that allows the excitation light E and the fluorescence F to pass therethrough satisfactorily. The indicator 19 may be the analyte 2 itself in which the fluorescent dye that does not contain the fluorescent dye and generates the fluorescent F exists in the solution.

  Hydrogel is water such as acrylic hydrogel produced by polymerizing monomers such as polysaccharides such as methylcellulose or dextran, acrylamide, methylolacrylamide, hydroxyethyl acrylate, or urethane hydrogel produced from polyethylene glycol and diisocyanate. It is formed by encapsulating a fluorescent dye in a material that is easy to contain.

  It is preferable that the hydrogel has a size that does not leave the sensor through the light shielding layer 18. For this reason, the hydrogel has a molecular weight of 1 million or more, or when the light shielding layer 18 has a porous structure, it is in the form of particles having a diameter larger than the pore diameter, for example, 50 nm or larger, or crosslinked. A form that does not flow is preferred.

  On the other hand, as a fluorescent dye, a phenylboronic acid derivative having a fluorescent residue is suitable for measuring saccharides such as glucose. The fluorescent dye is prevented from detaching from the sensor by using a high molecular weight material or chemically fixing to a hydrogel.

  The indicator is produced by allowing a phosphate buffer solution containing a fluorescent dye, a gel skeleton-forming material, and a polymerization initiator to stand for 1 hour in a nitrogen atmosphere and polymerize. For example, as the fluorescent dye, 9,10-bis [N- [2- (5,5-dimethylborinan-2-yl) benzyl] -N- [6 ′-[(acryloylpolyethyleneglycol-3400) carbonylamino ] -N-hexylamino] methyl] -2-acetylanthracene (F-PEG-AAm), acrylamide as the gel skeleton-forming material, sodium peroxodisulfate and N, N, N ′ as the polymerization initiator N'-tetramethylethylenediamine is used.

  In addition, since the indicator 19 which superposition | polymerization completed is a water-containing state, after drying until it becomes a predetermined | prescribed dry state, the sensor 30 becomes a finished product.

  Since the indicator 19 in the dry state has little change with time, even if the sensor 30 is stored for a long period of time, characteristics such as sensitivity during use do not change.

  The light shielding layer 18 forms an upper surface of the indicator space 16 in which the indicator 19 is accommodated, and prevents the excitation light E and the fluorescence F from leaking to the outside of the fluorescence sensor, and at the same time, external light enters the inside of the fluorescence sensor. To prevent that. Further, the light shielding layer 18 has biocompatibility, and the basic structure portion is hydrophilic so as not to prevent passage of a body fluid containing the analyte 2.

  For the light shielding layer 18, for example, a porous metal or ceramic, or a composite material in which fine particles that do not transmit light such as carbon black or carbon nanotubes are mixed with a hydrogel used for the indicator 19 is used.

  The sensor frame 17 has a function of protecting the sensor main body and a light shielding function, that is, a function of preventing entry of outside light and preventing leakage of light from the inside of the sensor to the outside of the sensor. The sensor frame 17 is made of a highly rigid material in order to protect the sensor body.

  The sensor frame 17 is made of a resin material such as silicon, glass or metal having a Young's modulus of several tens to several hundreds of GPa, or polypropylene or polystyrene having a Young's modulus of about 1 GPa to 5 GPa. In order to improve the light shielding function, black is used when glass or a resin material is used. As will be described later, the sensor frame 17 may be manufactured from a part of the substrate by processing the substrate 11.

  As described above, in the sensor 30, the dry indicator 19 is accommodated in the indicator space 16. The capacity of the indicator space 16 is substantially the same as the capacity of the swollen indicator 19, for example, 90% to 110% of the capacity of the swollen indicator 19. That is, as shown in FIG. 5, the indicator space 16 is almost filled with the swollen indicator 19 except for the residual gas region. That is, the indicator 19 swells in the shape of the indicator space 16.

  The size of the indicator space 16 is, for example, about 0.20 × 1.00 mm and a depth of about 0.05 mm when a commercially available small LED (size: 0.12 × 0.06 mm) is used as the LED element 14. Such an indicator space 16 can be easily manufactured using a semiconductor manufacturing technique, as will be described later.

  The indicator 19, that is, the hydrogel in a dry state does not mean that the moisture content is 0 wt%, and the indicator 19 contains water in such an amount that the change over time of the indicator 19 does not cause a practical problem as a sensor. Also good. Here, the water content is the weight of the indicator (water content 100%) which has been immersed in water for 1 hour and swelled, and the indicator heated at 100 ° C. for 12 hours in dry air or nitrogen (water content 0%). And the weight of the indicator to be measured (water content X%). Of course, when the weights of the indicators excluding water are different, correction is performed so that the weights are the same.

  For example, when the weight difference between the indicator having a moisture content of 0% and the moisture content of 100% is 100 mg, and the weight difference between the indicator to be measured and the indicator having a moisture content of 0% is 30 mg, the moisture content is 30 wt%.

  The indicator 19 of the sensor 30 before use preferably has a moisture content of 1 wt% to 25 wt%, particularly preferably 5 wt% to 10 wt%. If it is more than the said range, the water absorption speed | rate and light emission characteristic of the indicator 19 will not fall, and if it is below the said range, a time-dependent change will not be a problem.

<Operation of the fluorescence sensor system>
Next, the operation of the sensor system 1 will be described. As already explained, in the sensor 30, the indicator 19 is housed in the indicator space 16 in a dry state before use. For this reason, as shown in FIG. 7, when the indicator 19 absorbs water, it swells, that is, its volume increases and spreads inside the indicator space 16. For example, a water-containing hydrogel having a polymer component of about 10% has a volume of 10% to 50% of the water content when dried.

  That is, when the hydrogel, that is, the sensor 30 in which the indicator 19 is in a dry state is inserted (punctured) into the specimen for measurement, the sensor 30 comes into contact with a body fluid or the like, and the indicator 19 absorbs the body fluid and expands.

  Until the swelling of the indicator 19 is completed, the sensor 30 is not in a state where an accurate analyte concentration can be measured. However, the time required to complete the swelling of the indicator 19 varies depending on various factors, for example, the contact state between the light shielding layer and the body fluid or the discharge state of the gas in the indicator space 16. If the indicator 19 is not sufficiently swollen, there is a possibility that accurate measurement cannot be performed or the sensitivity is lowered. For this reason, the sensor 30 needs to set a waiting time until completion of swelling after puncturing and before starting measurement.

  The waiting time is set on the basis of the longest time required for completing the swelling of the indicator 19, for example. However, if the standby time is set, measurement data cannot be obtained until the standby time elapses even when the swelling is completed in a short time.

  On the other hand, the sensor 30 has the PD element 20 as a swelling detection sensor as already described. When the detection signal output from the swelling detection sensor (PD element 20) reaches a predetermined value, the control unit 42 starts measuring the analyte concentration.

  As shown in FIG. 8, for example, the intensity of the detection signal output from the PD element 20 is P0 when the indicator 19 is in a dry state, but decreases when the indicator 19 starts to swell and becomes stable when it reaches a predetermined value P1. That is, when the indicator 19 changes from a dry state to a water absorption state, the volume expands and the indicator space 16 is filled without a gap, and the refractive index increases due to water absorption. Then, since reflection and scattering at the interface are reduced, the excitation light E incident on the PD element 20 is reduced. When the indicator 19 is completely swollen, the excitation light E incident on the PD element 20 becomes substantially constant.

  Note that the completion of swelling when the indicator 19 is completely swollen does not mean that the state has reached a state where it no longer swells, and the indicator until the sensor 30 can perform stable measurement within a predetermined allowable range. It means that 19 has expanded.

  As already described, the time until completion of swelling varies depending on various factors such as temperature, puncture state (puncture angle, penetration depth), and puncture location. For example, in the case of A shown in FIG. 8A, the output becomes the predetermined value P1 at the time TA, but in the case of B or C, the output is the predetermined value P1 unless the time TB or the time TC has passed. do not become.

  In the sensor system 1, when the detection signal output from the PD element 20 is equal to or less than the predetermined value P1, the control unit 42 determines that the swelling is completed and starts measuring the analyte concentration. For this reason, the sensor system 1 does not require a long standby time and enables accurate measurement.

  The predetermined value P1 is appropriately set depending on the desired measurement accuracy. Note that the detection signal P may further decrease due to deterioration of the transparent intermediate layer 15 and the like by excitation light after the swelling of the indicator 19 is completed.

  As shown in FIG. 8B, when the differential value (change rate: dP / dT) of the detection signal output from the PD element 20 becomes equal to or less than a predetermined value ΔP1 (TD), the control unit 42 The measurement of the analyte concentration may be started by determining that the swelling has been completed. That is, the change rate of the detection signal usually has one peak with respect to time, and gradually decreases after the peak.

  Further, the control unit 42 may notify the user of a “warning” when the detection signal does not become the predetermined value P1 or less even after the predetermined time has passed, as in the case of D in FIG.

  In the sensor 30, the swelling detection sensor includes a PD element 20 that is a second photoelectric conversion element that converts the excitation light E generated by the LED element 14 into an electrical signal. For this reason, after the measurement of the analyte concentration is started, the PD element 20 can be used for applications other than the swelling detection sensor. For example, the PD element 20 is used as an excitation light monitoring element for monitoring the intensity of the excitation light E generated by the LED element 14, and the fluorescence detection signal of the PD element 12 is corrected based on the intensity of the monitored excitation light E. Also good.

  Further, it may be used as a temperature sensor by measuring the forward current of the PN junction of the PD element 20, and the fluorescence detection signal of the PD element 12 may be corrected based on the monitored temperature. Further, the PD element 20 may be alternately used as an excitation light monitoring element or a temperature sensor in time series.

Next, operation | movement of the fluorescence sensor system 1 is further demonstrated using FIG.
<Step S10>
In the sensor 30, the tip 32 is punctured into the subject.

<Step S11>
When the sensor 30 is connected to the main body 40, the excitation light A for swelling monitoring is pulsed from the LED element 14 by a driving power signal supplied via the connector 35 and the needle main body 33.

  The excitation light is also a cause of deterioration of the indicator 19 and the like. Further, in order to detect the swelling of the indicator 19, it is not necessary to generate strong excitation light like that for analyte detection. For this reason, it is preferable that the intensity | strength of the excitation light A is small with respect to the excitation light B for a measurement which the LED element 14 generate | occur | produces at the time of an analyte measurement. For example, in the excitation light B, the pulse width of light emission of the LED element 14 is 10 ms to 100 ms, the pulse current is about 1 mA to 100 mA, and the center wavelength of the excitation light is around 375 nm, for example, once every 30 seconds. Lights for several seconds. On the other hand, the excitation light A is preferably set so that the energy indicated by the product of the excitation light intensity and the emission time is, for example, 5 to 25% in the case of the excitation light B.

<Step S12>
When the excitation light A generated by the LED element 14 enters the PD element 20 by scattering and reflection, the excitation light A is converted into a swelling detection signal corresponding to the excitation light intensity, and the detection signal is transmitted to the control unit 42.

<Step S13>
The control unit 42 determines whether the detection signal is equal to or less than a predetermined value P1. When the detection signal is equal to or smaller than the predetermined value (Yes), the control unit 42 determines that the swelling of the indicator 19 is completed, and starts measuring the analyte from step S16.

  When the detection signal is not less than or equal to the predetermined value (No), the control unit 42 determines that the swelling of the indicator 19 has not been completed.

<Step S14>
The control unit 42 repeats the detection of the swelling of the indicator 19 from step S11 until a predetermined time has elapsed (No).

  On the other hand, when the predetermined time has elapsed (Yes), the control unit 42 notifies “warning” in step S15.

<Step S15>
“Warning” is based on sound, light, vibration or character display. The “warning” allows the user to know that the measurement cannot be performed correctly, and the punctured sensor 30 can be removed and punctured again or replaced with another sensor 30.

<Step S16>
When the controller 42 detects the completion of the swelling of the analyte from the detection signal of the swelling detection sensor (LD element 20), the controller 42 starts measuring the analyte concentration. In the measurement of the analyte concentration, the LED element 14 is controlled so as to generate excitation light B for analyte measurement stronger than the excitation light A.

<Step S17>
The PD element 12 receives the fluorescence generated by the indicator 19 due to the interaction between the excitation light B and the analyte, converts it into an electrical signal, and transmits it to the control unit 42.

<Step S18>
The control unit 42 controls the PD element 20 as a temperature sensor and receives a temperature signal.

<Step S19>
The control unit 42 controls the PD element 20 as an excitation light intensity sensor and receives an excitation light intensity signal.

<Step S20>
The control unit 42 transmits the received fluorescence signal, temperature signal, and excitation light intensity signal to the receiver 45. Note that the control unit 42 may correct the fluorescence signal using the temperature signal and the excitation light intensity signal, and transmit the corrected fluorescence signal.

<Step S21>
The processing from step S16 is repeated until there is an instruction to end the analyte measurement. Step S18 (temperature signal detection) or step S19 (excitation light intensity signal detection) may be performed at a different time interval from step S17 (fluorescence signal detection). For example, step S18 and step S19 may be performed every time step S17 is performed five times. Further, step S18 and step S19 need not be performed.

  As described above, the fluorescence sensor system 1 and the fluorescence sensor 30 can start accurate measurement in a short time.

Second Embodiment
Next, the sensor system 1A and the sensor 30A of the second embodiment will be described. Since the sensor system 1A and the sensor 30A according to the present embodiment are similar to the sensor system 1 and the sensor 30 according to the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIGS. 10 and 11, in the sensor 30 </ b> A, the swelling detection sensor includes a plurality of second photoelectric conversion elements (PD elements) 21 to 24. The PD elements 21 to 24 are arranged in the vicinity of the four corners of the sensor frame 17 that reaches the end when the indicator 19 expands.

  The control unit 42 determines that the swelling of the indicator 19 is completed when all the detection signals of the four PD elements 21 to 24 are equal to or less than the predetermined value P1.

  The sensor 30A may detect the completion of swelling based on the total value of the detection signals of the four PD elements 21 to 24, or may swell based on the time differential values of the detection signals of the respective PD elements 21 to 24. Completion may be detected, or completion of swelling may be detected based on the difference between the detection signals of the PD elements 21 to 24 being a predetermined value or less.

  Sensor system 1A and sensor 30A have the effect which sensor system 1 and sensor 30 have, and can determine the completion of swelling of indicator 19 more reliably.

  In the sensor system 1A having a plurality of PD elements 21 to 24, when the PD elements 21 to 24 are used as excitation light intensity sensors or temperature sensors at the time of analyte measurement, more information is obtained. It can be acquired.

<Third Embodiment>
Next, the sensor system 1B and the sensor 30B of the third embodiment will be described. Since the sensor system 1B and the sensor 30B according to the present embodiment are similar to the sensor system 1 and the sensor 30 according to the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIGS. 12 and 13, in the sensor 30 </ b> B, the sensor frame 17 and the substrate 11 are made of a semiconductor such as silicon, the PD element 12 is formed on the inner wall of the sensor frame 17, and the PD is formed on the surface of the substrate 11. Element 20 is formed. The PD element 12 is provided so as to surround the indicator 19 (indicator space 16), and is formed so that the light receiving surface faces the indicator 19.

The PD element 12 may be formed on the entire inner wall, but may be formed only in a region facing the indicator 19 in order to efficiently receive only the fluorescence F. The PD element 12 may be formed on all four inner walls, or may be formed on only a part of the surfaces.
That is, the PD element 12 may be formed on at least a part of the inner wall of the sensor frame 17.

  A filter 13 is disposed on the PD element 12. The filter 13 is formed on the light receiving surface side of the PD element 12 so as to cover the PD element 12.

  Since the PD element can be formed on the inner wall of the substrate 11 and the sensor frame 17, the PD element 20 is formed on a part of the sensor frame 17, and the PD element 20 other than the PD element 20 forming part of the sensor frame 17 and the substrate The element 12 may be formed.

  The sensor 30B has the effect of the sensor 30 and the like, and further has a high detection sensitivity because the PD element 12 formed on the side surface surrounding the indicator 19 detects the fluorescence F.

<Fourth embodiment>
Next, the sensor system 1C and the sensor 30C of the fourth embodiment will be described. Since the sensor system 1C and the sensor 30C of this embodiment are similar to the sensor system 1B and the sensor 30B of the third embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 14, in the sensor 30C, the PD element 12 is formed on the four side surfaces of the rectangular concave portion formed on the substrate 11C made of a semiconductor such as silicon, and the PD element 20 is formed on the bottom surface of the concave portion. Yes.
That is, in the sensor 30C, the sensor frame can be regarded as the outer peripheral portion of the recess formed in the substrate 11C.

  The opening surface of the recess is wider than the bottom surface, and the side surface is not perpendicular to the bottom surface but is inclined at a predetermined angle θ. In addition, the board | substrate 11C which has a recessed part may be produced by joining the frame-shaped sensor frame board | substrate used as a recessed part, and a plane board | substrate.

  Next, a method for manufacturing the sensor 30C will be briefly described. In addition, although it may manufacture for every sensor 30C, it is preferable to manufacture many sensors collectively as a wafer process.

  In the manufacturing process by the wafer process, first, a mask layer having a plurality of mask portions is manufactured on a first main surface of a silicon wafer having an area where a plurality of elements can be manufactured. Then, a plurality of recesses having a bottom surface parallel to the first main surface is formed by an etching method.

  As an etching method, a wet etching method using a tetramethylammonium hydroxide (TMAH) aqueous solution, a potassium hydroxide (KOH) aqueous solution, or the like is preferable, but dry etching such as reactive ion etching (RIE) or chemical dry etching (CDE) is used. Can also be used

  For example, when a silicon (100) surface is used as a silicon wafer, the etching speed of the (111) surface is slower than that of the (100) surface, so that the side surface of the recess becomes the (111) surface. The angle with the (100) plane (bottom surface) is 54.7 degrees.

  Next, the PD element 12 is formed on the four side surfaces of each recess, and the PD element 20 is formed on the bottom surface of the recess by a known semiconductor process. The concave portion whose side surface is inclined has not only a large area where the PD element 12 can be formed, but also the formation of the PD element 12 on the side surface is easier than the concave portion whose vertical side surface is vertical. Hard to remain. In addition, the said effect is remarkable if the inclination-angle of a side surface is 30-70 degree | times.

  Next, the filter 13 is disposed on the PD element 12 on the side surface. Next, the LED elements 14 are respectively disposed on the bottom surfaces of the plurality of recesses. Further, after forming the transparent intermediate layer 15, a buffer solution serving as an indicator 19 is filled in the recess. Further, the light shielding layer 18 is bonded so as to close the opening of the recess. Then, the silicon wafer on which a plurality of sensors are formed is separated into individual pieces to complete the sensor 30C. The drying process may be performed in a wafer state or after being separated into individual pieces.

  The sensor 30C has the effects of the sensor 30B and is easy to manufacture.

  In the above description, a sensor that detects saccharides such as glucose has been described as an example of a fluorescent sensor. However, a fluorescent sensor may be an enzyme sensor, a pH sensor, an immune sensor, a microbial sensor, or the like depending on the selection of a fluorescent dye. It can be used for various purposes.

  Moreover, although the photoelectric conversion element was illustrated as a swelling detection sensor, a swelling detection sensor may consist of a some electrode and may detect swelling with an electrical resistance. Since the fluorescence sensor having the swelling detection sensor composed of a plurality of electrodes does not irradiate the indicator with excitation light for swelling detection, the indicator is unlikely to deteriorate.

  That is, the present invention is not limited to the above-described embodiments and modifications, and various changes and modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 1A-1C ... Fluorescence sensor system 2 ... Analyte 10 ... Sensor part 11 ... Board | substrate 12 ... PD element 13 ... Filter 14 ... LED element 15 ... Transparent intermediate | middle layer 16 ... Indicator space 17 ... Sensor frame 18 ... Light shielding layer 19 ... Indicator 20 ... PD element 30, 30A-30C ... Fluorescence sensor 40 ... Main body part 42 ... Control part 45 ... Receiver 50 ... Sheath tube

Claims (12)

A substrate,
A first photoelectric conversion element that converts fluorescence into an electrical signal;
A sensor frame constituting a side surface of an indicator space in which an indicator made of a hydrogel that generates fluorescence by an analyte and excitation light is accommodated in a dry state;
A filter disposed so as to cover the photoelectric conversion element and transmitting the fluorescence and blocking the excitation light;
A light emitting element that generates the excitation light, disposed in the sensor frame;
A transparent intermediate layer disposed on the light emitting element and constituting a lower surface of the indicator space, disposed in the sensor frame;
A light-shielding layer that constitutes the upper surface of the indicator space, shields external light and the excitation light, and allows a body fluid containing the analyte to pass through;
A fluorescence sensor comprising: a swelling detection sensor that detects swelling of the indicator due to the body fluid entering the indicator space.   The fluorescence sensor according to claim 1, wherein the swelling detection sensor includes a second photoelectric conversion element that converts the excitation light into an electric signal.   The fluorescence sensor according to claim 2, wherein the first photoelectric conversion element and the second photoelectric conversion element are photodiodes formed on the substrate made of a semiconductor.   The fluorescence sensor according to claim 3, wherein the swelling detection sensor includes a plurality of the second photoelectric conversion elements.   5. The device according to claim 1, wherein at least one of the first photoelectric conversion element and the second photoelectric conversion element is formed on an inner wall of the sensor frame. Fluorescent sensor.   The fluorescent sensor according to claim 5, wherein the sensor frame is an outer peripheral portion of a recess formed in the substrate.   7. The analyte concentration of the body fluid is continuously measured based on the intensity of the fluorescence generated by the indicator that is placed in a living body and contains water. 8. The fluorescent sensor according to item. The fluorescent sensor according to any one of claims 1 to 7,
A main body having a controller connected to the fluorescent sensor and controlling the operation of the fluorescent sensor;
The fluorescent sensor system, wherein the control unit starts measuring an analyte concentration based on a detection signal output from the swelling detection sensor.   The fluorescence sensor system according to claim 8, wherein the control unit starts measuring the analyte concentration when the detection signal output from the swelling detection sensor becomes a predetermined value or less.   9. The fluorescence sensor system according to claim 8, wherein the control unit starts measuring the analyte concentration when a differential value of the detection signal output from the swelling detection sensor becomes a predetermined value or less. .   The said control part measures excitation light intensity using the said 2nd photoelectric conversion element which is a photodiode at the time of the measurement of the said analyte density | concentration, The any one of Claims 8-10 characterized by the above-mentioned. 2. The fluorescence sensor system according to item 1.   The said control part measures temperature using the said 2nd photoelectric conversion element which is a photodiode at the time of the measurement of the said analyte density | concentration, The any one of Claims 8-11 characterized by the above-mentioned. The fluorescent sensor system described.

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